Heating furnace



Jan. 11 1927' H. JUNKERS .HEATING FURNA Filed June 7, 1924 Patented Jail. 11, 1927.

UNITED STATES HUGO JUNKERS, 0F DESSAU, GERMANY.

HEATING FURNACE.

Application filed June 7, 1924, Serial No.

This invention relates to heating furnaces utilizing fuels or heating agents of any kind. v In heating furnaces operated by a heating agent the temperature varies consider ably along the path of'the heating gases, and the surfaces which radiate the heat outwards when directly heated by the heaing gases, reach excessive tOlllPOl'tltlll'OS nearest to the inlet of the heating gases. This gives rise to certain, drawbacks, for example, burning of the dust deposited on the surface, destruction of the heating fines by the high temperature and acid content of the heating gases, and escape of the heating gases at defective spots. These drawbacks could only incompletely be avoided by known eonstructions, in which a large flame chamber and a double walled top part, connected thereto, are used, as the irregular distribution of temperatures was not avoided and the furnace needed large dimensions, without totally extracting the heat from the combustion gases. p

The object of the present invention is to" obtain, in heating furnaces, an-approximatei ly uniform surface temperature, which will not exceed the highest limit considered as permissible, in all parts of the heat-radiating flues. This is achieved by leading'a current of heating gases from a burner to a flue or chimney through an inner shell surrounded by an outer shell at such decreasing distance, that said outer shell is heated from the directly heated shell by radiation up to surface temperatures which are approximately uniform in all parts.

Further details of my invention will be hereafter described.

To enable the invention to be fully understood, it will now be described by reference to the accompanying drawings, in which:

Fi g. 1 is a section showing a coal furnace,

Fig. 2 is a sectional side view of a radiartor like gas furnace constructed according to the invention, and 3 Fig. 3 is a front view thereof, partly in section on the line V-V, Fig. 2.

Fig. 4 is a sectional view on line VIVI Fig. 2.

Fig.1 shows a heat-ing arrangement with a grate for solid fuel. The heating arrangement consists of two concentric shells or tubes 1", 2", a flue connected to the outer shell 2 for removing'the waste gases, and a combustion chamber forming a bottom clos- 718,581, and in Germany March 3, 1923.

ing the end of the space, bounded by the tubes. The inner tube 1 is exposed to the direct influence of the heating gases, while the outer tube 2" is separated from the inner. tube by a stagnant layer of air, and is bathed on its outer side by the air to be heated. Consequently, the outer tube is heated from the inner tube in an indirect manner, by radiation. By suitably calculating the distances between the directly heated inner tube and the outer tube it is possible, in conjunction with the diminishing temperature of the heating gases, to'obtain a practically uniform temperature over thewholelength of the outer tube without said temperature anywhere exceeding the highest limit regarded as permissible. In this case, the inner tube 1 does not extend 'as far as the point of exit of the waste gases from the heating arrangement, but only up to a height at which the temperatureof the heating gases has already fallen to such a degree that, although from that point onwards, the

. heating gases are in direct contact with the outer tube 2, the surface temperature of this latter tube does not exceed the desired value.

. As shown in Figs. 24, a gas heating fur nace according to the invention is built up of a plurality of sectional elements consisting each of an inner shell 1 traversed by the heating gases, and an outer shell 2 surrounding the former at a certain distance. The shells 1 are secured on a combustion chamber 5, which is open below and that the resulting gases of combustion ascend through the shell 1. The outer shells 2 taper in the upward direction from the point of entry of the heating gases and their tapered upper ends discharge into a'collecting chamber 8, provided with a chimney flue 7 for the waste gases. In their lower part they are widened laterally and are fitted together by the lateral edges of the widenings, was to form an outer casing, which envelopes the combustion chamber 5 and at the lower ends is connected thereto, so that a closure for the space bounded by the two shells 1, 2 is formed. The inner shells 1 are not carried rightup to the collecting chamber 8 and therefore the heating of the outer shells 2 is effected, up to the point of exit of the heating gases from the temperature of the heating gases has fallen to the degree permissible for the shells 2 that the heating gases, after issuing from the inner shell 1 come into direct contact with a portion of the shell 2, before passing into the collecting chamber 8 and thence a burner, a plain walled shell arranged for encircling the flame of said burner with its lower part and extending upward from said burner so as to enclose the current of heating gases delivered by said burner, a second plain walled shell surrounding and spaced concentrically from said first shell to form a relatively small space therebetween, means tightly closing the space between the lower ends of said shells to prevent air from entering and heating gases from passing through said space, so that the outer shell is heated solely by radiation from the first named shell, the distance between the two shells being greater near the source of heating gases and smaller in the other parts, in accordance with, the surface temperatures of the directly heated shell, and a flue at the top of the shells for removing the Waste heating gases.

2. A heating furnace as in claim 1 in which said outer shell extends further upward than said first shell in the direction of current and said outer flue-is connected to the top of said outer shell.

3. In a heating furnace, incombination, a burner, a combustion chamber arranged for encircling the flame of said burner, a plurality of'mner shells extending upward from said combustion chamber so as to enclose the current of heating gases delivered by said burner, an outer casing enveloping said combustion chamber at a certain distance, means tightly closing the space between the lower .ends of said combustion chamber and easing, a plurality of outer shells extending upward from said casing and surrounding at a relatively small space said inner shells, and a fiue connected to the top of said outer shells for removing the waste heating ases.

In Witness wiereot I affix my signature.

HUGO JUNKERS. 

